<template>
  <div>
    <div class="goods">
<div class="menu-wrapper" ref="menuWrapper">
      <ul>
        <!--  current -->
        <li class="menu-item" v-for="(good,index) in goods" :key="index"
        :class="{current: index===currentIndex}" @click="clickMenuItem(index)">
          <span class="text bottom-border-1px">
            <img class="icon" :src="good.icon" v-if="good.icon">
              {{good.name}}
          </span>
        </li>
</ul>
</div>
<div class="foods-wrapper" ref="foodsWrapper">
<ul ref="foodsUl">
<li class="food-list-hook" v-for="(good,index) in goods" :key="index">
<h1 class="title">{{good.name}}</h1>
<ul>
  <li class="food-item bottom-border-1px" v-for="(food, index) in good.foods" :key="index" @click="showFood(food)">
    <div class="icon">
    <img width="57" height="57" :src="food.icon">
    </div>
    <div class="content">
    <h2 class="name">{{food.name}}</h2>
    <p class="desc">{{food.description}}</p>
    <div class="extra">
    <span class="count">月售 {{food.sellCount}} 份</span>
    <span>好评率 {{food.rating}}%</span></div>
    <div class="price">
    <span class="now">￥{{food.price}}</span>
    <span class="old" v-if="food.oldPrice">￥{{food.oldPrice}}</span>
    </div>
      <div class="cartcontrol-wrapper">
      <CartControl :food="food"></CartControl>
      </div>
    </div>
  </li>
  </ul>
</li>
</ul>
</div>
<ShopCart></ShopCart>
</div>
<Food :food="food" ref="food"></Food>
</div>
</template>

<script>
import BetterScroll from 'better-scroll'
import {mapState} from 'vuex'
import CartControl from '../../../components/CartControl/CartControl.vue'
import Food from '../../../components/Food/Food.vue'
import ShopCart from '../../../components/ShopCart/ShopCart.vue'
export default {
  data() {
    return {
      scrollY:0, //右侧滑动的Y轴坐标(滑动过程时实时变化)
      tops:[], //所有右侧分类li的top组成的数组  (列表第一次显示后就不再变化)
      food:{},//需要显示的food
    }
  },
  components:{
    CartControl,
    Food,
    ShopCart
  },
  mounted() {
    this.$store.dispatch('getShopsGoods')
  },
  computed:{
    ...mapState(['goods']),
    // 计算得到当前分类的下标
    currentIndex(){
      // 得到条件数据
      const{scrollY,tops} = this
      // 根据条件计算产生一个结果
      const index = tops.findIndex((top,index)=>{
        return scrollY>=top && scrollY<tops[index+1]
      })
      // 返回结果
      return index
    }
  },
  watch:{
  goods(newValue){
  this.$nextTick(()=>{ //一旦完成界面更新，立即调用
    this._initScroll()
    this._initTops()
  })
  }
},
methods: {
  // 初始化滚动条
  _initScroll(){
    new BetterScroll('.menu-wrapper',{
      
   })

   this.foodsScroll = new BetterScroll('.foods-wrapper',{
     probeType:2
   })
  //  给右侧列表绑定scroll监听
  this.foodsScroll.on('scroll',({x,y})=>{
    console.log(x,y);
    this.scrollY = Math.abs(y)
  })
  //  给右侧列表绑定scroll结束的监听
  this.foodsScroll.on('scrollEnd',({x,y})=>{
    console.log('scrollEnd',x,y);
    this.scrollY = Math.abs(y)
  })
  },
  // 初始化tops
  _initTops(){
    // 1、初始化tops
    const tops = []
    let top = 0
    tops.push(top)
    // 2、收集
    // 找到所有分类的li
    const lis = this.$refs.foodsUl.getElementsByClassName('food-list-hook')
    Array.prototype.slice.call(lis).forEach(li=>{
      top+=li.clientHeight
      tops.push(top)
    })
    // 3、更新数据
    this.tops = tops
    console.log(tops);
  },
  clickMenuItem(index){
    // console.log(index);
    // 使右侧列表滑动到对应的位置
    const y = -this.tops[index]
    this.foodsScroll.scrollTo(0,y,300)
  },
  // 显示点击的food
  showFood(food){
    // 设置food
    this.food = food
    // 显示food组件(在父组件中调用子组件对象的方法)
    this.$refs.food.toggleShow()
  }
},

}
</script>

<style lang="stylus" rel="stylesheet/stylus">
  @import "../../../common/stylus/mixins.styl"
  .goods
    display: flex
    position: absolute
    top: 195px
    bottom: 46px
    width: 100%
    background: #fff;
    overflow: hidden
    .menu-wrapper
      flex: 0 0 80px
      width: 80px
      background: #f3f5f7
      .menu-item
        display: table
        height: 54px
        width: 56px
        padding: 0 12px
        line-height: 14px
        &.current
          position: relative
          z-index: 10
          margin-top: -1px
          background: #fff
          color: green
          font-weight: 700
          .text
            border-none()
        .icon
          display: inline-block
          vertical-align: top
          width: 12px
          height: 12px
          margin-right: 2px
          background-size: 12px 12px
          background-repeat: no-repeat
        .text
          display: table-cell
          width: 56px
          vertical-align: middle
          bottom-border-1px(rgba(7, 17, 27, 0.1))
          font-size: 12px
    .foods-wrapper
      flex: 1
      .title
        padding-left: 14px
        height: 26px
        line-height: 26px
        border-left: 2px solid #d9dde1
        font-size: 12px
        color: rgb(147, 153, 159)
        background: #f3f5f7
      .food-item
        display: flex
        margin: 18px
        padding-bottom: 18px
        bottom-border-1px(rgba(7, 17, 27, 0.1))
        &:last-child
          border-none()
          margin-bottom: 0
        .icon
          flex: 0 0 57px
          margin-right: 10px
        .content
          flex: 1
          .name
            margin: 2px 0 8px 0
            height: 14px
            line-height: 14px
            font-size: 14px
            color: rgb(7, 17, 27)
          .desc, .extra
            line-height: 10px
            font-size: 10px
            color: rgb(147, 153, 159)
          .desc
            line-height: 12px
            margin-bottom: 8px
          .extra
            .count
              margin-right: 12px
          .price
            font-weight: 700
            line-height: 24px
            .now
              margin-right: 8px
              font-size: 14px
              color: rgb(240, 20, 20)
            .old
              text-decoration: line-through
              font-size: 10px
              color: rgb(147, 153, 159)
          .cartcontrol-wrapper
            position: absolute
            right: 0
            bottom: 12px
</style>